mm: introduce page_size()
Patch series "Make working with compound pages easier", v2.
These three patches add three helpers and convert the appropriate
places to use them.
This patch (of 3):
It's unnecessarily hard to find out the size of a potentially huge page.
Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).
Link: http://lkml.kernel.org/r/20190721104612.19120-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f1e0569..639d5e7 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -878,7 +878,7 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
head = compound_head(page);
v += (page - head) << PAGE_SHIFT;
- if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head))))
+ if (likely(n <= v && v <= (page_size(head))))
return true;
WARN_ON(1);
return false;
